Selenoprotein O Promotes Melanoma Metastasis and Regulates Mitochondrial Complex II Activity

Area of Science:

• Biochemistry
• Oncology
• Cell Biology

Background:

• Selenoprotein O (SELENOO) is an evolutionarily conserved enzyme catalyzing AMPylation, crucial for oxidative stress response.
• Oxidative stress in the bloodstream impacts melanoma cell survival and metastatic potential.
• The role and substrates of mammalian selenoprotein O in cancer remain largely unelucidated.

Purpose of the Study:

• To investigate the role of selenoprotein O (SELENOO) in promoting cancer metastasis.
• To identify mammalian mitochondrial substrates of SELENOO.
• To elucidate the mechanism by which SELENOO influences melanoma progression.

Main Methods:

• Analysis of SELENOO expression in melanoma patients and correlation with clinical outcomes.
• Utilizing a murine model of spontaneous melanoma metastasis to assess the effect of SELENOO deficiency.
• Biochemical assays to identify and characterize SELENOO's mitochondrial substrates, including succinate dehydrogenase subunit A.
• Measuring mitochondrial complex II activity in SELENOO-deficient cells.

Main Results:

• High SELENOO expression in melanoma patients correlated with increased metastasis and poorer survival.
• SELENOO deficiency significantly reduced metastasis in a murine melanoma model, an effect reversible by N-acetylcysteine.
• SELENOO was found to AMPylate mitochondrial substrates, notably succinate dehydrogenase subunit A (a component of mitochondrial complex II).
• SELENOO-deficient cells exhibited enhanced mitochondrial complex II activity.

Conclusions:

• SELENOO promotes melanoma metastasis by modulating mitochondrial function and oxidative stress.
• Targeting SELENOO-mediated posttranslational modification of mitochondrial substrates presents a potential strategy for cancer therapy.
• SELENOO plays a significant role in cancer progression, particularly in melanoma metastasis.